June 2003
Organ Ciphers	Show Menu

Stephen Adams

Why do organs cipher? (I bet whoever asked that in the first place is sorry by now!)

I will assume you have in front of you the last issue of "SOUNDBOARD". The sketch on p.3 is a very revealing section of a typical 3 manual organ, but don’t forget, it is a section at only one place. Therefore, for instance, we will find 56 (or whatever the compass is) trackers, squares, stickers….. 56 of everything to do with the manual key actions. And lots of stuff has been omitted for clarity (wind system, stop action). So it gets complicated.

I assume you can follow the chain of events (?) When a key is pressed it pulls or pushes the square "C", which converts the force from vertical to horizontal, and so on, until the action terminates at the pallet.

I don’t think it’s over-simplifying it by saying that if there’s any problem with any of these parts, that we will have trouble.

Typical problems: starting at the keyboard, what’s not drawn is the means to arrest the upward travel of each key. This is usually done using a heavy but pliable piece of metal, called the thumper. This allows the "off" position of the keys (i.e. the height) to vary a little, according to seasonal conditions.

Imagine the Swell soundboard’s supporting frame. It will be supported using hefty timbers, maybe 6" × 6". The squares "C" will also be supported from the same frame, at a lower level.

Then take an unusually dry period. The trackers "L" will react to this quicker than the building frame, getting shorter at a faster rate. Therefore the height of the keys will rise as the tension on the trackers increases, thus increasing the key depth (i.e., raising the keys).

Since the Swell is almost always the highest division in the organ, it is affected more than other divisions because its action is longer.

To demonstrate — say the Swell action is 3 m long, and the Great is 1 m long – it only takes a change in tracker length of 0.1% and the Swell will change by 3 mm, whilst the Great by 1.0 mm. Many modern trackers have compensation designed into them to accommodate such dimensional fluctuations — it’s a tricky business.

break the tracker (which will cause a dumb note) it’ll effectively shorten its length, and of course the key will not lift due to the thumper, so the only variable thing left is the pallet, which will open. Indeed, sometimes the pallet can open under extreme conditions, either from an accident (or just enthusiastic playing) and hop up on its own guide pins, causing a cipher that requires access to the soundboard internally. Looking generally at the drawing, it’s good to appreciate why an organ is laid out like it is. There are obvious things such as height, interms of fitting the components at all. However, this organ is well laid out for maintenance/tuning access. See how the tuner has passage boards to stand on, right next to the stops that most need maintenance, the reeds? See also how the reeds are situated Stephen Adams, Organ builder. The net effect of the action becoming shorter is for the Swell action to become deeper relative to the Great or Choir. This will make the couplers contact at an earlier point such that, by the time the drawstop is pulled out fully, we have multi-ciphers and you can visibly see and feel the keys being pulled down.

The opposite happens too of course, where the action becomes longer and lowers the action depths — couplers can become ineffective, not pulling through fully.

(A clever way to overcome this is to site the couplers as far away from the keyboards as possible, thus lessening the effect on the keys — not something that can be retrofitted.)

So the thumper can move, and the depth of the action can vary according to climate. A common source of a cipher is for a paperclip or similar to work its way in over the key and under the thumper. If you have a cipher and you lift the key and the cipher stops, then this is a possible cause — worth having a peep using a torch.

Other reasons for ciphers are many and varied. A common problem would be excess friction at any pivot point. Builders used to use steel for the pivot points, and of course this rusts and causes problems.

Another fairly common thing is for a hymnbook or similar to fall onto the horizontal trackers. If it doesn’t directly over the pallets, to get the first flush of air in the interest of prompt speech.

The opposite happens too, where a complaint is received about the speech of bottom C of the Swell Open Diapason! Now that’s a sod!

Something not clear from the drawing is the purpose of the parts labelled "BC". We call this the rollerboard. If you’re sitting at the keyboard, the keyboard is say, 2’ wide. However, the soundboard(s) might well be 8’ wide, and so the spacing of the trackers at the keyboards (circa.1/2") will not suit the spacing of the pulldowns and pallets. So, a rollerboard carries the action sideways, whatever direction and amount that is required to make the key and pallet align and join.

The organ in the drawing is fully tracker. However, there are pneumatic or electric actioned organs, and mixes of different types. And indeed, every organ is different.

This quick glimpse at the workings will not fully educate, but hopefully engender appreciation. If it does that, then I have been successful.

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